A new postdoctoral fellow position will start on 1 November 2015 at the Technion – Israel Institute of Technology. The position is in the area of theoretical and computational modeling of dynamic failure in soft solids. The potential candidate should have a Ph.D.
In the laminar mode interactions
among molecules generate friction between layers of water that slide with
respect to each other. This friction triggers the shear stress, which is
traditionally presumed to be linearly proportional to the velocity gradient.
The proportionality coefficient characterizes the viscosity of water. Remarkably,
the standard Navier-Stokes model surmises that materials never fail – the transition
to turbulence can only be triggered by some kinematic instability of the flow. This
premise is probably the reason why the Navier-Stokes theory fails to explain
The application of mechanics to biology
– biomechanics – bears great challenges due to the intricacy of living things.
Their dynamism, along with the complexity of their mechanical response (which
in itself involves complex chemical, electrical, and thermal phenomena) makes
it very difficult to correlate empirical data with theoretical models. This
difficulty elevates the importance of useful biomechanical theories compared to
other fields of engineering. Despite inherent imperfections of all theories, a
Macroscopic
cracks do not appear as a result of an ideal separation of two adjacent atomic
layers. Just the opposite, cracks appear as a result of the development of
multiple micro-cracks triggered by the massive breakage of atomic bonds. The microcracking
and the bond breakage are not confined to two neighbor atomic planes: the
process involves thousands atomic planes within the representative characteristic
volume of size h. This size defines the width (not the lenth) of the damage
localization zone and it can be called the crack thickness. The knowledge of
All models are wrong, but some are useful. This famous saying mirrors the situation in cell mechanics as well. It looks like no particular model of the cell deformability can be unconditionally preferred over others and different models reveal different aspects of the mechanical behavior of living cells. The purpose of the present work is to discuss the so-called tensegrity models of the cell cytoskeleton. It seems that the role of the cytoskeleton in the overall mechanical response of the cell was not appreciated until Donald Ingber put a strong emphasis on it.
I finished the grad course on Mechanics of Soft Materials. It took 14 weeks with 2 academic hours per week and it covered the following topics: 1 Tensors 2 Kinematics 3 Balance laws 4 Isotropic elasticity 5 Anisotropic elasticity 6 Viscoelasticity 7 Chemo-mechanical coupling 8 Electro-mechanical coupling.
I attach the class notes and I will be grateful for the remarks, corrections, and criticism from iMechanicians.
Let us consider interaction of two atoms/molecules/particles. The reference distance between them corresponds to zero interaction force and zero stored energy. The interaction passes three stages with the increase of the distance. At the first stage the force increases proportionally to the increasing distance: the linear stage. At the second stage the force-distance relationship deviates from the linear proportionality: the nonlinear stage. At the third stage the force drops with the increasing distance: the separation or failure stage.
